The goal of this research is provide a statistical basis for improved methodology in the screening and diagnosis of hypertension through a more complete description of the within - person variability of arterial blood pressure and the mutual dependence of a series of measurements on an individual. A new statistical model has been developed by these investigations which provides the framework for this descripition. Older models provide basis for computing the amount of regression to the mean in screening studies and for computing the probability of misclassification and for the use of an average repeat observations to reduce those factors. But the older methods do not treat the effect of time period between first and second screen or the effect of the spacing between multiple measurements. The new model takes these factors into account in a manner which allows for computation of more accurate expressions for regression to the mean and probability of misclassification. In addition we have developed, with the aid of this model, a new approach to assessing the diagnostic information in a series of measurements on an individual. In order to implement these results for practical application, the parameters of the model must be evaluated for various subgroups. We have, in our computer files, a large data base from which many of he necessary results can be obtained. In this application we seek the funds necessary to carry out the analysis of this data base and to translate the results into working tools for researchers and practitioners in hypertensive disease.